INTERTAN与PFNA治疗Evans-Jensen Ⅳ型股骨转子间骨折的有限元分析

Finite element analysis of INTERTAN and PFNA for treatment of Evans-Jensen type Ⅳ of intertrochanteric fracture

目的通过有限元分析对股骨近端防旋髓内钉(PFNA)和INTERTAN髓内钉治疗Evans-JensenⅣ型股骨转子间骨折的生物力学特点进行对比,为Evans-JensenⅣ型股骨转子间骨折的治疗提供一定的理论依据。方法建立股骨以及INTERTAN、PFNA三维有限元模型(分别为I模型、P模型),分析模型中正常股骨和两组内固定的应力分布,比较正常股骨及内固定模型各区域的应力峰值,分析INTERTAN、PFNA的生物力学稳定性。结果两组模型股骨的应力模式与正常股骨相同,主要位于股骨近端内侧及股骨中段内侧,但两组模型股骨应力较正常股骨相同部位应力均有不同程度升高。I、P两组模型股骨应力峰值为均位于股骨近端内侧,分别为61.827MPa、66.382MPa;内植物应力峰值均位于主钉与远端锁钉相交处,分别为72.554MPa、75.486MPa;股骨最大应变(ε)均位于股骨中段内侧,分别为1421×10^-6、1525×10^-6。结论PFNA和INTERTAN均可用于Evans-JensenⅣ型股骨转子间骨折的治疗。相较于PFNA,INTERTAN具有一定的生物力学优势。

Objective To compare the biomechanical characteristics of proximal femoral nail anti-rotation(PFNA)and INTERTAN intramedullary nail in the treatment of Evans-Jensen type IV intertrochanteric fracture by finite element analysis,in order to provide a theoretical basis for the treatment of Evans-Jensen type IV intertrochanteric fracture.Methods Three-dimensional finite element models of femur,INTERTAN and PFNA were established,the stress distribution of normal femur and two groups of internal fixation in the model was analyzed.The stress peak in different regions of normal femur and internal fixation models was compared.The biomechanical stability of INTERTAN and PFNA was analyzed.Results The stress pattern of femur in the two groups of models was the same as that of the normal femur,mainly located in the medial proximal femur and the medial part of the femur.However,the femoral stress of the two groups of models was higher than that of the normal femur in the same part.The femur peak stress of model I was 61.827 MPa,and was located in the proximal medial femur.The femur peak stress of P model was 66.382 MPa,located in the proximal medial.The peak stress of implant in I and P models was located at the intersection of the main nail and the distal locking nail,which was 72.554 MPa and 75.486 MPa,respectively.In model I,the maximum strain(ε)of the femur was 1421×10^-6,l,and was located in the medial part of the femur;in model P,the maximum strain(ε)of the femur was 1525×10^-6,and was located in the medial part of the femur.Conclusion PFNA and INTERTAN can be used in the treatment of Evans-Jensen type IV intertrochanteric fracture.Compared with PFNA,INTERTAN has certain biomechanical advantages.